The relatively widespread and ever increasing utilization of high quality fiber optic materials, usually glass or optical plastic, for use in optical wave guide communication systems, data processing and other signal transmission systems has created a demand for satisfactory and efficient means of interjoining terminal ends of adjacent fiber lengths without appreciable loss of signal energy through the junction. It has been found that such terminal ends of the fibers transmit light energy signals with minimum loss of signal when the end of the fiber itself is optically flat with a mirror smooth surface lying in a plane perpendicular to the longitudinal axis of the fiber filament.
In the early stages of employing fiber optic filaments, a variety of methods and techniques were developed, many involving rough, imprecise cutting of the fiber using scissors, side cutters, or similar cutting tools which, however, produced a ragged, crooked, cracked or non-perpendicular optically irregular surface on the fiber filament. These rough end surfaces were then cast in epoxy of plastic and ground and polished to a perpendicularly oriented, optically correct surface. In still other instances, hand-held or cumbersome bench mounted tools, involving fiber scribers and cutters, usually fixedly mounted and made of hardened metal or diamond sharpened to a conical or chisel formation, have been used for scoring the fiber materials. In such prior tool developments, the fiber is normally supported on its bottom side over a supporting surface while it is being scored. In still later developments, it was discovered that by bending the fiber over a curved surface during the scoring operation, sufficient tension was imposed on the fiber filament to produce a relatively clean cleavage or break surface thereon. However, in the bending-tensioning operations because part of the fiber filament is under compression while the remainder thereof is under tension, an optically inferior surface results at the break plane through the filament. These inferior surfaces are normally compensated for by using an optical refractive matching fluid or by grinding and polishing the same to correct the defects.
By and large, past efforts in this art have failed to develop a consistently dependable system for achieving an optically perfect end surface in and along the fracture plane of the glass or other rigid fiber optic material. One of the difficulties in such past efforts has centered about the utilization of rigid scribing instruments such as a fixedly mounted ground diamond point which, when moved across the surface of the glass fiber, produces a torsional load on the fiber, creating unwanted forces in the fiber body susceptible of producing errant fractures which are damaging to an optically perfect break surface. Additional deficiencies in such prior known score and cleave tools reside in their inability to accommodate fibers of differing diameters and characteristics, the incapabability, as mentioned, of providing uniformed tensile stress along the axis of the fiber to effect a clean mirror and optically perfect break surface, the inability to regulate the radial forces with which the fiber is gripped and held in a tool and the lack of any means for regulating the scoring pressure and attack angle of the scribing instrumentality employed, whether it be a ground diamond or hardened metal. In other instances, particularly in the hand held or hand operated tools, the operating forces applied by the operator's hand to effectuate the sequence of events, are reflected in and vary the forces imposed on the fiber itself. This is particularly undesirable inasmuch as uniformity of cutting conditions are required to obtain a consistently repeatable capability of cleaving the fibers with optically correct end surfaces.
Typifying some of the prior developments embodying the general features as hereinabove discussed are the following U.S. patents: U.S. Pat. No. 3,934,773 issued to Chinnock et al; U.S. Pat. No. 3,981,422 issued to J. R. Moore; U.S. Pat. No. 4,017,013 issued to Hawk et al; U.S. Pat. No. 4,027,814 issued to Gloge et al; U.S. Pat. No. 4,074,840 issued to Fulenwider et al; and U.S. Pat. No. 4,168,026 issued to Lucas et al. The scribe-and-cleave methods and instrumentalities disclosed in the above listed patents generally include the steps of scribing or scoring and applying tensile stress to the fiber for purposes of propagating the scribe or score plane diametrically through the fiber which is commonly supported by a backing member or anvil having or movable into a curved configuration to facilitate the application of the tensile forces.